SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Wear, beyond Engine Manual limits, has been identified on the abutment faces of the splines on the Trent 900 Intermediate Pressure (IP) shaft rigid coupling on several engines during strip. The shaft to coupling spline interface provides the means of controlling the turbine axial setting and wear through of the splines would permit the IP turbine to move rearwards.

Rearward movement of the IP turbine would enable contact with static turbine components and would result in loss of engine performance with potential for in-flight shut down, oil migration and oil fire below the LP turbine discs prior to sufficient indication resulting in loss of LP turbine disc integrity. We are issuing this AD to detect rearward movement of the IP turbine, which could result in loss of disc integrity, an uncontained failure of the engine, and damage to the airplane.

DATES: This AD becomes effective September 17, 2010.

Of course it is far too early to say if this has anything to do with the Trent 900 engine failures experienced by Singapore Airlines and Qantas on their A 380’s but the AD does talk about the possibility of an “uncontained failure of the engine”.

A Qantas A380 has been forced to return to Singapore’s Changi Airport after pilots were forced to shut down one of its four engines. QF32 was bound for Sydney with 443 passengers and 26 crew on board when the engine failed. “Qantas flight QF32 was en route from Singapore to Sydney, the number two engine has shut down, so as a precautionary measure we are taking it back to Singapore,” a Qantas spokeswoman said.

The wrecked engine after the plane landed in Singapore.Photo: AFP

Indonesian authorities said there had been some sort of explosion over the island of Batam, just south of Singapore. Elfhinta radio quoted a police officer in Batam, Eryana, saying parts of the plane had been found. “We are still collecting debris,” he said.

In a recent similar incident, an engine exploded on a Qantas flight to San Francisco on August 30, with debris tearing holes in the engine cover.

An engine problem on a Singapore Airlines A380 superjumbo airliner was a “non-event” in technical terms, the chief executive of the company that built it said yesterday. Singapore Airlines said the plane carrying 444 passengers from Paris to Singapore was forced to return to the French capital on Sunday when the as-yet unspecified problem was detected two and a half hours into the flight.

The A380 is the world’s largest passenger airliner and Singapore Airlines (SIA) is the first to take delivery of it, having ordered 19 with an option for six more. Speaking in Paris, Louis Gallois, chief executive of Airbus manufacturer EADS, called the incident “a complete non-event”.

“Engine failure on a four-engine aircraft does happen and nobody should think of it as a drama,” Gallois told journalists. “In technical terms, it is not an event.”

The A380 can be fitted with two types of engines: A380-841, A380-842 and A380-843F with Rolls-Royce Trent 900, and the A380-861 and A380-863F with Engine Alliance GP7000 turbofans. The Trent 900 is a derivative of the Trent 800, and the GP7000 has roots from the GE90 and PW4000. The Trent 900 core is a scaled version of the Trent 500, but incorporates the swept fan technology of the stillborn Trent 8104. The GP7200 has a GE90-derived core and PW4090-derived fan and low-pressure turbo-machinery. Only two of the four engines are fitted with thrust reversers.